Index: src/OFArray.h
==================================================================
--- src/OFArray.h
+++ src/OFArray.h
@@ -67,11 +67,11 @@
  * \brief Creates a new OFArray with the specified objects, terminated by nil.
  *
  * \param firstObject The first object in the array
  * \return A new autoreleased OFArray
  */
-+ (instancetype)arrayWithObjects: (id)firstObject, ...;
++ (instancetype)arrayWithObjects: (id)firstObject, ... OF_SENTINEL;
 
 /**
  * \brief Creates a new OFArray with the objects from the specified array.
  *
  * \param array An array
@@ -102,11 +102,11 @@
  * \brief Initializes an OFArray with the specified objects.
  *
  * \param firstObject The first object
  * \return An initialized OFArray
  */
-- initWithObjects: (id)firstObject, ...;
+- initWithObjects: (id)firstObject, ... OF_SENTINEL;
 
 /**
  * \brief Initializes an OFArray with the specified object and a va_list.
  *
  * \param firstObject The first object

Index: src/OFDictionary.h
==================================================================
--- src/OFDictionary.h
+++ src/OFDictionary.h
@@ -99,11 +99,11 @@
  * \brief Creates a new OFDictionary with the specified keys objects.
  *
  * \param firstKey The first key
  * \return A new autoreleased OFDictionary
  */
-+ (instancetype)dictionaryWithKeysAndObjects: (id)firstKey, ...;
++ (instancetype)dictionaryWithKeysAndObjects: (id)firstKey, ... OF_SENTINEL;
 
 /**
  * \brief Initializes an already allocated OFDictionary.
  *
  * \return An initialized OFDictionary
@@ -159,11 +159,11 @@
  *	  and objects.
  *
  * \param firstKey The first key
  * \return A new initialized OFDictionary
  */
-- initWithKeysAndObjects: (id)firstKey, ...;
+- initWithKeysAndObjects: (id)firstKey, ... OF_SENTINEL;
 
 /**
  * \brief Initializes an already allocated OFDictionary with the specified key
  *	  and va_list.
  *

Index: src/OFObject.h
==================================================================
--- src/OFObject.h
+++ src/OFObject.h
@@ -44,16 +44,22 @@
 #endif
 
 #ifndef __has_feature
 # define __has_feature(x) 0
 #endif
+
+#ifdef __GNUC__
+# define __GCC_VERSION__ (__GNUC__ * 100 + __GNUC_MINOR__)
+#else
+# define __GCC_VERSION__ 0
+#endif
 
 #if defined(__clang__)
 # define OF_HAVE_PROPERTIES
 # define OF_HAVE_OPTIONAL_PROTOCOLS
 # define OF_HAVE_FAST_ENUMERATION
-#elif defined(__GNUC__) && (__GNUC__ * 100 + __GNUC__) >= 406
+#elif __GCC_VERSION__ >= 406
 # define OF_HAVE_PROPERTIES
 # define OF_HAVE_OPTIONAL_PROTOCOLS
 # define OF_HAVE_FAST_ENUMERATION
 #endif
 
@@ -69,10 +75,14 @@
 # undef YES
 # define YES __objc_yes
 # undef NO
 # define NO __objc_no
 #endif
+
+#if defined(__clang__) || __GCC_VERSION__ >= 406
+# define OF_SENTINEL __attribute__((sentinel))
+#endif
 
 #if __has_feature(objc_arc)
 # define OF_RETURNS_RETAINED __attribute__((ns_returns_retained))
 # define OF_RETURNS_NOT_RETAINED __attribute__((ns_returns_not_retained))
 # define OF_RETURNS_INNER_POINTER __attribute__((objc_returns_inner_pointer))